Abus de position dominante et monopole

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Chess game symbolizing dominance

What is abuse of dominance o‌r monopolisation?

A firm’s ability to raise its prices is usually constrained by competitors and the possibility that its customers can switch to alternative sources of supply. When these constraints are weak, a firm is said to have market power and if the market power is great enough, to be in a position of dominance or monopoly (the precise terminology differs according to the jurisdiction). While mere possession of monopoly power does not in itself constitute violation of competition laws, the abuse of such power  - particularly if it is used to weaken competition further by excluding rivals - calls for intervention from competition authorities.


Detecting abuse of dominance

Determing when a firm’s behaviour is an abuse of market power, as opposed to a competitive action, is one of the most complex and controversial areas in competition  policy.  Competition laws typically contain provisions prohibiting abuse of market power by dominant firms or attempts of not yet dominant firms to monopolise markets.


However, there is considerable divergence among jurisdictions about the precise definition of dominance, the range of practices and conducts that should be condemned as anti-competitive, and finally the choice of remedies that should be imposed.

Examples of abusive practices typically include:

  • predatory pricing
  • loyalty rebates
  • tying and bundling
  • refusals to deal
  • margin squeeze
  • excessive pricing

‌A proper understanding of when a firm’s actions could be considered abusive is important for competition authorities because consumers’and the economy would be harmed by an incorrect intervention. A firm with a large market share, which might be considered dominant, also needs to understand the law and economics in this area, which is not always easy.


To promote effective enforcement of competition laws in the area of abuse of dominance and monopolisation, the OECD Competition Committee holds roundtable discussions, typically with the participation of businesses, academics and other interested participants.  As a result, Best Practice Roundtables proceedings are published to provide some guidance to best practices in this area, at the cutting edge of applied competition law and policy.

For further information on the OECD work related to abuse of dominance and monopolisation, please contact us at


Documents and links

List of all roundtable on Abuse of Dominance


Latest roundtables on Abuse of Dominance

Safe harbours and legal presumptions in competition law, 2017

Competition issues in aftermarkets, 2017

Multi-sided markets: Rethinking the Use of Traditional Antitrust Enforcement Tools, 2017

Big data: Bringing competition policy to the digital era, 2016

Geographic market definition across national borders, 2016

Price discrimination, 2016

Commitment Decisions in Antitrust Cases, 2016

Fidelity rebates, 2016

Competition and cross platform parity agreements, 2015

Oligopoly Markets, 2015

OECD inventory of international co-operation agreements on competition, 2014

Enhanced Enforcement Co-operation, 2014 

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